At 22:00 March 17 JST (09:00 am Thursday March 17 ET) JAIF issued the latest status report on Fukushima Daiichi. 

Unit 3 and 4 Spent Fuel Pools

Immediate threat is damage of the fuels in the fuel pool outside the containment vessel at Unit-3 and Unit-4. To improve the situation of lack of water in the spent fuelpools at Unit-3 and Unit-4, Japan Self-Defense Force (JSDF) started operation for filling the pool with water in 09:48 of March 17. This operation is to drop a huge bucketof seawater from a helicopter. In addition, the police and JSDF [Japan Self Defence Force] implemented watering operation toward Unit-3 using their water cannon truck and fire engines in theevening. The effect of these operations is under evaluation.

Status of Fukushima #1 power station as of 21:30, March 17, 2011 (08:30 am Thursday March 17 ET)
“Operations for filling the pool with water at unit-3” (appears to be based on reports from NHK)

* 1st operation
Japan Self-Defense Forces dropped 4 huge buckets of seawater from helicopters
in this morning. Lead plates were installed at the bottom of the helicopters to
shield radiation and crew members wore radiation protection suits.

* 2nd operation
The National Police Agency tried to pour water from the ground with pumper
truck in the evening. However, they were not able to come close because of high
radiation and water did not reach the pool.

* 3rd operation
Japan Self-Defense Forces poured 30 tons of water from the ground with 5
special pumper trucks from 19:45 to 20:09. Because these trucks are special, they
were able to do this operation without getting off the trucks. Effect of this
operation is under evaluation.

Radiation Measurement at plant perimeter (not new)

646.2μSv/h at 11:10, Mar. 17 (10:10:00 p.m. Wednesday March 16,)